muhammed: Make linux-builder more accesible

Using breakpointHook [0], one can jump into the sandbox of a failing
build. This is very useful for debugging. However, building
packages inside the linux-builder VM adds an extra layer of abstraction.

This patch makes a few changes which make it easier to work:

- cntr, which is used to attach to the sandbox, is now included on the
  builder
- You can now sign in to the root user of the VM using the password
  "root". This is required because cntr must be run as root.

[0]: https://www.youtube.com/watch?v=ULqoCjANK-I

1 files changed, 19 insertions, 0 deletions

diff --git a/hosts/muhammed/configuration.nix b/hosts/muhammed/configuration.nix
index 4959dbb..96564fb 100644
--- a/hosts/muhammed/configuration.nix
+++ b/hosts/muhammed/configuration.nix
@@ -43,6 +43,25 @@
   nix.settings.trusted-users = ["linus"];
   nix.linux-builder = {
     enable = true;
+
+    # Clearing the VM state upon startup should improve reliability at the cost
+    # of some startup speed. Will have to re-evaluate if this trade off is
+    # worth it at some point.
+    ephemeral = true;
+
+    config = {pkgs, ...}: {
+      environment.systemPackages = with pkgs; [
+        # cntr is used to jump into the sandbox of packages that use breakpointHook.
+        pkgs.cntr
+
+        # Nix is used to debug and fetch other tools as needed.
+        pkgs.nix
+      ];
+
+      # Allow root login. This would normally be horrible but it's a local VM so who cares.
+      users.users.root.hashedPassword = "$y$j9T$TosKLKCZ.g9be.Wz5/qVJ.$YWvn4nAp8tn.xhHGBMOz748PHma6QGhN/WShilEbz8A";
+      services.openssh.permitRootLogin = "yes";
+    };
   };
 
   # System-specific version info.